1. Field of the Invention
The present general inventive concept generally concerns an image forming device. More specifically, the present general inventive concept is directed to an image forming device capable of calculating a life span of a consumable component by reflecting an environment of the image forming device and a method thereof.
2. Description of the Related Art
The prevalence of a computer has given rise to that of peripherals such as an image forming device including, for example, a printer, a copier, a fax machine, and a multifunctional machine. The image forming device commonly adopts a structure and a working principle of the printer which prints certain data onto a printing paper.
The structure of the printer is divided into a control part and an engine part. The control part interprets image data from a computer, stores the interpreted data into a memory of the printer, and transfers the stored data in a form of serial data after communicating with the engine part so that the engine part performs a printing operation.
The engine part is a mechanical component which prints onto the printing paper the print data transferred from the control part. The engine part of a laser printer may include an organic photoconductive drum (hereinafter, refer to as a photoconductive drum), a writing part, a developing part, a charging part, a transferring part, and a fusing part.
FIG. 1 illustrates a construction of the engine part of the laser printer. Referring to FIG. 1, when a printing paper 11 is fed from a feeding part 10, the charging part 50 charges a surface of the photoconductive drum 30 with a negative charge using a charging wire or a rubber roller. The rubber roller is generally used for the charging. The surface of the photoconductive drum 30 is charged with −600V to −1000V DC by closely contacting the rubber roller with the surface and applying a voltage of a predetermined range.
The writing part 40 exposes a laser beam onto the surface of the photoconductive drum 30 using a laser scanning unit (LSU), and produces a latent image by neutralizing the scanned area. The developing part 20 develops the latent image to a visible image by attracting a toner onto the surface of the photoconductive drum 30 using a developing roller.
The toner on the surface of the photoconductive drum 30 is transferred onto the printing paper 11. The transferring part 60 closely contacts a transferring roller to a back side of the printing paper 11, applies an electrostatic force through a corona discharge by applying a high positive voltage so that the toner is transferred onto the printing paper since the electrostatic force is greater than adhesion of the toner to the photoconductive drum 30.
The fusing unit 70 fixes the toner on the printing paper 11 using a press roller 71 and a heating roller 72, and the printed paper is discharged.
Still referring to FIG. 1, the engine part may include a certain part, such as the transferring roller of the transferring part 60 and a charging roller of the charging part 50, of which an operating condition may change depending on an overall environment. The overall environment of the certain part is checked and its operating condition is correspondingly set prior to the operation.
FIG. 2 illustrates the transferring roller 61 which closely contacts the photoconductive drum 30 with the printing paper put between the photoconductive drum 30 and the transferring roller 61. The transferring roller 61, which is a critical part of the transferring part 60, is a kind of a rubber roller including an iron core 61b and a rubber 61a. When the voltage is applied through the iron core 61b, the positive charge is discharged onto the surface of the rubber 61a, thus transferring the toner.
The rubber 61a of the transferring roller 61 is apt to be affected by the environment, such as temperature or humidity, so that its resistance may vary. However, since the voltage for the transferring is uniform, the resistance of the transferring roller 61 is measured and the voltage applied to the iron core 61b is adjusted according to the measurement, to thus maintain suitable transferring current irrelevant of the resistance. Namely, the transferring roller 61 needs the adjustment of the operating condition, that is, the applied voltage depending on the environment. The charging roller of the charging part 50 may be a rubber roller, and also requires a uniform voltage. The uniform voltage of the charging roller is applied as in the transferring roller 61.
Each part of the laser printer has a limited life span and replacement time. For example, the more usage of the rubber 61a of the transferring roller 61 results in a greater resistance. The transferring may not be normally performed after printing more than a predetermined number of sheets since the suitable transferring voltage cannot be maintained.
Accordingly, the image forming device counts and accumulates a number of revolutions of a pickup roller (not shown), which is a part of the feeding part 10 for picking up and feeding the printing paper 11, so as to determine the replacement time of each part. When the accumulated number of the printed papers is compared with and exceeds a preset number of the printed papers of each part, the image forming device determines the replacement.
However, the conventional image forming device determines the replacement time of each part without consideration of its environment, which may not correspond to the actual replacement time. Solidity of the rubber of the rubber roller may vary significantly depending the temperature and the humidity, and accordingly, its resistance may vary. Specifically, a high transferring voltage is required in low temperature and low humidity since the resistance increases due to static electricity on the surface of the printing paper and increased solidity of the rubber. The more the printed papers are yielded, the more the solidity of the rubber increases. As a result, the resistance continuously increases so that the life span of the rubber roller is shortened as compared with normal temperature and humidity. Conversely, the life span of the rubber roller is lengthened in high temperature and high humidity since a relatively low transferring voltage is applied.
Since the conventional image forming device does not consider the environment of each part, the still available component may be replaced in the high temperature and humidity, and the exhausted component is not replaced in the low temperature and humidity so as to depreciate the quality of the printed image. These problems may arise not only to the transferring roller but also to the other parts of which the replacement times are different from each other depending on the environment even when the replacement time is determined based on the number of the printed sheets.